The search became complicated when crews realized that at high tide at about 2:30 a.m. a strong current removed a “huge quantity of the sandy material” and carried it out to sea, said Charlie Strickfaden, a spokesman for the Golden Gate National Recreation Area.

After crews sifted through the debris Saturday, it was not known by midafternoon if the missing woman’s body was still buried on the beach or if it was swept into the ocean, Strickfaden said.

The incident occurred at 2:38 p.m. Friday when a dirt mound the size of a tractor trailer broke loose. The cliffside rolled over two women, who bystanders said were walking a dog on the beach, said Lt. Jonathan Baxter, a spokesman for the San Francisco Fire Department.

“We had two adults with one canine that were trapped underneath there,” Baxter said Friday. “Bystanders were able to rescue one of those victims and the canine. Our firefighters are working diligently in an effort to locate the second adult victim, which is reported to be a female.”

On Saturday, crews used dozers and hand shovels to search through the sand. Canines were also deployed during the recovery effort. There were no plans to use boats or aircraft to search the water because it posed dangers to rescue workers and it is unlikely the body would still be at the surface of the water, Strickfaden said.

Crews monitored the area and continued ground searches Saturday. It was not yet decided if recovery efforts would continue Sunday.

“Our thoughts go out to the friends and the family of the missing woman,” he said. “We consider this an unfortunate, natural, tragic event.”

The woman who was rescued was buried up to her shoulders in sand when she was found by bystanders, Strickfaden said. The woman, who was not identified, was transported to a hospital with minor injuries. She has spoken to investigators but is “obviously in shock,” he added.

On Saturday, nearly a half dozen police vehicles were parked near where the incident occurred. Police tape held back the dozens of passersby walking their dogs.

Johnny Poon, 55, said he saw a small bulldozer driving toward the beach when he walked past the area. Like many others out for a morning stroll, he was saddened to hear about what had happened.

“We just stay on the path,” the South San Francisco resident said. “A lot of people fall down the cliff, so you just have to be careful.”

Sarah Ravani covers Oakland and the East Bay at The San Francisco Chronicle. She joined The Chronicle in 2016 after graduating from Columbia University's Graduate School of Journalism. Previously, she covered breaking news and crime for The Chronicle. She has provided coverage on wildfires, mass shootings, the fatal shooting of police officers and massive floods in the North Bay.